The Central Laboratory for Human Embryology is the nation's largest and most efficient laboratory specializing in collection, study, description and distribution of human embryos, fetuses and their tissues. During the past 22 years over 8000 specimens have been collected. In addition, to research performed with this material within this laboratory, nearly 250 other investigators have collaborated with us and this research was dependent on our unique ability to rapidly obtain, analyze and distribute human embryonic and fetal samples. These efforts have resulted in nearly 450 publications to date. By virtue of extensive experience in analysis of the human conceptus, we are able to serve as a monitoring system for congenital anomalies in the abortus. The search for novel defect patterns and changes in frequencies of patterns is aided by the years of experience of the laboratory and its personnel as well as by the relationships which have been long established with obstetricians and pathologists in our collection area. Because of the inherent difficulty of extrapolation from animal teratogen tests, we believe that monitoring of the abortus represents an invaluable tool in surveillance for potential teratogens. The numerous embryonic and fetal growth and development standards published by this laboratory along with periodic summaries of embryonic and fetal pathology make this surveillance possible. Current collaborative efforts include establishment of human genomic libraries, synthesis of monoclonal antibodies and study of oncofetal antigens. Additionally, this laboratory maintains a major collection of intact and serially sectioned human embryos and gross fetuses. Newer techniques of embedding and staining this material enable more precise studies of human development than have been possible in the past. During the past 12 years, using a computerized information up-date system, laboratory personnel have been able to provide data on animal tests and human risks of teratogenic agents to a large number of local and national workers. The data has been published.